Apparatus for baking or drying substances at high temperatures and for subsequently cooling same



July 2z, 1924. 1,502,186

. R. GREENWOOD APPARATUS FOR BQKING OR DRYING SUBSTANCES AT HIGH yTEMPERATURI'JS AND FOR SUBSEQUENTLY. COOLING SAME Filed Dec. 6. 1921 5 Sheets-Sheet l ffy/WM July 422 1924. 1,502,186

R. GREENWOOD APPARATUS FOR BAKING OR DRYING SUBSTANCES AT HIGH TEMPERATURES AND FOR SUBSEQUENTLY COOLING SAME l Mym.

July 22, 1924. y 1,502.186

R. GREENWQOD APPARATUS FOR BAKING 0R DRYNG sUBsTANCEs AT` HIGH TEMPERATURES AND FOR SUBSEQUENTLY COOLING SAME Filed Dec.6 1921 5 Sheets-Sheet 5 july 22, 1924. 1,502,186

R. GREENWOOD APPARATUS FOR BAKING 0R DRYING sUBsTANCEs AT HIGH TEMPERATURES AND FOR SUBSEQUENTLY COOLING SAME -Filed Dec. 6. 1921 5 Sheets-Sheet 4 July 22. 1924. 1,502,186

R. GREENWOOD APPARATUS FOR BAKING OR DRYING SUBSTANCES AT HIGH TEMPERATURIJS AND -FOR SUBSEQUENTLY COOLING SAME Filed Deo. 6 192] 5 SheetsfSheet 5 Patented July 22, 19.24.`

l UNITED. STATES PATENT OFFICE. f

EOwLAND GREENWOOD, or OAELISLE, ENGLAND, AssIeNOEOE ONE-HALE 'ro CARR i e COMPANY LIMITED, OP CARLISLE, ENGLAND, A BRITISH COMPANY.

APPARATUS FOR BAKING OEDRYING sBs'rANcEs A'r HIGH TEMPERATURES A ND 'Foa sUBsEQUEN'rLY COOLING SAME. c

Application mea 1mm-.mbarv e, 1921. serial No. 520,377.

To all-whom izfmayv concern.' Y

Be it known that I, 4RowLAND' GREEN- WOOD, a subject of the King of Great Britain and Ireland,'residing at 4 Morton Terrace, Wigton Road, in the cityof Carlisle,'coun ty of Cumberland, England, have' invented a new and useful Apparatus for Baking or Dr in 'Substances at High-Tem eratures andI or Subsequently Cooling ame, of which the following is a specification. v

This invention relates to apparatus 'for drying or lbaking substances, such for example as biscuits for food,fat high tem eratures and has for its object to provi e an oven and cooling tower adapted to co-operate automatically in dealing continuously with the substances under treatment and to provide further an improved system for supplying air for heating and cooling to the Oven and cooling tower respectively.

According to the inventiony substances to be;` baked or dried "are caused to ascend in continuous succession through an-air heated oven and-to descend through a cooling tower at a slower speed. Heated air is supplied to the oven through a number of inlets independently controllablewhilst the air .circu ation through the cooling tower is arranged invsuch a manner that an air lock is formed arouncl'the point at which the Vbaked,

yor dried lsubstances are transferred auto-1v Figure 4 is a sectional elevation throu hthe Oven and cooling tower taken on t e line B-B of Figure 3, e

Figure 5 is a plancorrespondin to Figure 4- with the tops of the oven an cooling tower removed,

- Figure 6 is a view showing the relative positions of the various controls on the extrior of the oven, and

Figure 7 is a sectional elevation through the heater forV supplyinghot air to the oven.

The main component parts of the apparatus comprise an oven 1, a cooling tower 2,' an air heaterl and va fan 5 vfor a1r circulation.

The oven and cooling-tower each consist of iin insulated sheet iron cased tower the insulation being less in the case of the coolin tower than in that of the oven. The su ,stance to be treated is conveyed inpans or trays by suitable feeding gear of the endat 6, Figure 1, into the base of the oven tower 1 where each tray is engaged by lifting gear y adapted to convey it to the top-of the oven.

`irons provide supports 'or shelves for tra s 14 of substances to be dried or bakedas t e -latter are` fed in to the oven by 'the conveyor 6. As the chains move vindthe direc-` tion of the arrows C a cntiiilous succession y, of trays 14 will pass through the oven each bein supported on a pair of angle irons 13.

e `cooling tower 2 is arranged intere nall in. a manner similar to the oven with env ess chains 1 5, 16, 17 and 18 rotated in a direction contrary to thechains 7-10 by sprocket wheels 19 at the top of the tower and passing around sprocket wheels 2O at the base of the tower.

. As -the trays 14approach the top of the oven they are ltransferred one by one to the cooling tower by change over gear now toy be described. Two'endless conveyorsQl preferably in the form of sprocket chains, move horizontal] in the direction indicated by the arrow Figure 4', between the chains 7,

65 less conveyor type shown diagrammatically 3 and' 9, 16. The chains 21 are also connected by equidistantly spaced angle irons 22, in the present instance ffour being employed, the projecting portions of which en' gage the edges of trays 14 remote from the cooling tower and push the trays into the lattei` on to angle irons 23 which are` carried by chains 15, 16 and 17, 18 respectively,lthe

-trays thereafter being lowered through the cooling tower.- The conveyors 21 are actuated by sprocket wheels 24. As the trays are transferred from oven to cooler the movement imparted to them will he arrested by the outer wall 25 of the cooler, any rebound of a tray will be taken ioy the inclined edge 26 of the insulated wall dividing the'oven from the cooler. When conditions require the speed of the conveyors in the cooling tower'to be slower than that of those in the oven as described hereinafter the number ci' angle irons employed willbe greater lin the cooling tower j and they vwill be disposed closer together. y

rllhe conveying arrangementsabove de lscribed are driven from a main power shaft is operated. @n the shaft 31 are mounted s the pair of sprocket wheels 24 which is nearer the cooling tower 2 (Figure 4),.

At the upper end of shaft 31 is mounted' a bevel gear 32 meshing with a second, bevel gear 33 fast on a horizontal shaft 34 carried in bearings on the side of the oven. This shaft 34 carries a spur wheel 35 meshing with. a second spur wheel 36 mounted on a shaft 37 parallel to the shaft 34 andpassing through the top of the oven and extending across the top of the cooling tower. A third spur wheel 38 equal in diameter and number of teeth with the wheel 36 is'mounted on a shaft 39 and meshes with the said 'wheel 36. The shafts 37 and 39 carry the sprocket wheels 11 whichI drive the oven conveyor chains 7, 8, 9 and 10.

On the end of shaft 37 remoteffrom the spurwheel 36 is mounted a pinion 4Q meshing with `a spur wheel 41 mounted on a shaft 42 which carries one pair of the sprocket wheelsv 19 by-which the cooling tower conveyor 'chains 15, 16, 17 and 18 are driven. The second pair of'sprccket vwheels 19 is mountedon a shafty 43 on the end of which is carried a spur wheel 44 similar in all respects to the wheelV 41 and meshing therewith. 1 The gear ratio between the spur wheel 41 and pinion 4() being in the present instance 3 to 1, it follows. that the trays 14 will be caused to descend the cooling tower at one-third the. speed of4 their ascent through the oven. The speed ratio, however, can be varied in accordance with the :escasas substances to he treated in the oven, dit ferent classes of biscuits for example requiring different treatment in cooling.

At the base of the cooling tower is disposed a pair of endless conveyors 45 similar in construction and operation to' the change over gear'already described and by means of which the trays 14 are removed. from the cooling towerand delivered towa'ny suitable arrangement for conveying the dried or baked products to storage.

Having described the mechanical arrangements hy which substances to be dried or baked are progressed through the oven and cooling tower, themeans employed for heat- `in g and circulating air will now be described. i

Air for circulation through the oven 1 is heated in a heater which may comprise (ligure .7) a number of conduits 3 ofsubstantially rectangular cross section extending through aninsulated casing 4. Air entering through inlets 59y in the base of the casing passes acrossv the tops of the conduits l 3 to .an outlet 60 communicating with the vinterior of the oven 1. Each conduit is formed with a curved upper surface from whichl project a number of heat distributing members 61, the lexterior of each of which is Vgrooved or provided with fins 62. These conduits are disposed preferably in two groups as .shown each group consisting of Y `a number of superimposed pairs of conduits.

The air' to be heated is compelled to take a tortuous vpath in ascending owing to baffles 63 disposed between the conduitsin the two groups and baliles 64 alternating with the bailes 63 and disposed between the conduits and the walls of the heater.

Within` each conduit3are disposed rows of burners 65, when gas or oil is used as the heating medium, each jet being disposed lpreferably' vertically beneath one of the heat distributors 61. One endof each eonduit is adapted for the entry of air for combustion by forced drau ht or induction whilst the opposite end 1s connected to a iue for the outlet of gases of combustion.

By making the conduits deeper in relation to their width and inserting fire bars, hard fuel'can be emplo ed whilst the construction of the conduits is such that it readily lends itself to heating by electrical means. v

In the arrangement illustrated the outlet 60 delivers heated air to one or more air trunks formed within the oven 1. In the present instance two inlet trunks or sections 49 are employed disposed diagonally and alternately` with two exhaust trunks 50 connected to the inlets 59 in the base of the heater, a continuous -circulation through theseS trunks being maintained by the fan 5 which is placed 1n an inlet duct connected to both trunks 49. These inlet and exhaust sacarse y stances to be baked Aor dried disposed on the Y trays. 14. This action .is effected by deiiectors or louvres 52 (see Figure 2) disposed in sets adjacent each air inlet 51 and between thekascending and-descending sections ot each of the chains 7, 8, 9 and 10. By arranging for the independent manipulation of each set of louvres from a point external to the oven, top or'bottom heating can `be applied as desired to the trays as they ascend.

Air which has given up its heat to the substance under treatment returns through opening aL through the exhaust trunks 50 to the heater 4 a constant circulation being maintained by the fan 5.

A draught of cool airis caused to enter the cooling tower at its base as through openings 2a, one of which is shown in F igure 1,v and becomes gradually heated as it ascends, the -heated air leaving, the tower through outlets 46. These outlets are arranged below the point at which the trays 14 are transferred from the oven to the cooling tower and in this manner a body ot residual air fills the top of the cooling. tower constituting an air lock to prevent escape othot airfrom the oven.

Thecooling arrangement described above is particularly advantageous in cooling biscuits baked in'the oven as the biscuits near-- est `the delivery end (the base) of the cooling tower will Areceive the full cooling eti'ect of the incoming air whilst the biscuits higher up the tower will get the benefit of the tempered air. In this manner cracking of biscuits through harsh or too sudden cooling will be avoided.'

For the purpose of controlling the temperature of the oven and ensuring that its `moving contents `are exposed to the correct temperature at dierent oints it has been found convenient to divi e the 'oven finto' a number of sections such as those indicated by .the lines I--I, III-II, III- III and IV-IV in Figure 1 each of these sectionsl 'to the temperatures indicated by these gauges, the baiiies 48 and louvres 52 are adjusted. V53 indicates the operating rods 'o'r the louvres disposed in the upper sections and 54v similar rods for the louvres in the lower sections. 55 indicates the operating rods for the batiies 48 in the upper sections, 56 similar rodsvor the battles in the sections next below and 57 a handle for operating the lowermost baille. The oven may be provided also with a vent 58 at the top for the escape of any excess moisture caused by the evaporation of liquids in the oven.

f In applying the invention to the baking of biscuits a great saving in space and labour is elected besides carrying out the operations of baking and cooling at a greater speed than has been the case hitherto.

'In this case the delivery conveyor may be geared in ratio with the oven conveyors so that the biscuits pass direct from the cutting. machine to the oven and through the latter and the cooling tower entirely by mechanical operation. It will be understood that modifications may be made in the details of the yarrangements described without departing from the invention. For example, instead of the conveying gear in the oven and cooling tower comprising four endless chains or belts, six may be used in each case. This enables'better provision to be made against breakdown as the apparatus would continue to function if one chain became broken or 4othervise put out of action.

I claim 1. A baking apparatus comprising an oven, means causing substances to be baked to ascend through said oven, means for controlling the temperature of said oven at various points, a cooling tower, means causing baked substances to descend said tower,

and meagre causing the temperature of saidV tower to decrease towards its base.

2. A baking apparatus comprising an oven, an air heater, a plurality of inlets for heated air in said oven, lmeans rendering said inlets independently controllable, means for conveying substances upwards throughsaid oven, a cooling tower, means for automatically transferrin baked substances from the oven to sai cooling tower, and

ducing cooling air.

means in the base of'said tower for intro- 3. A baking yapparatus comprising a vertical oven, an air heater, a plurality of inlets for heated air in said oven, means rendering said inlets independently controllable, conveying means maintaining continuous movement within said oven of the substances to be treated, independently controllable means for detlecting hot air on the substances under treatment, a cooling tower, means for transferring baked substances from said oven to said cooling tower, means for maintaining continuous movement Within said cooling tower of. the ,I baked substances, and means for cooling said 4baked substances gradually l in said cooling tower.

4. A baking apparatus comprising an insulated vertical oven, an air heater, a plurality of independently controllable inlets in said oven connected with said heater, ex-

haust outlets from said oven to said heater,I

means adapted to convey a series of trays bearing substancesto be treated through sa1d oven, a cooling tower disposed adjacent said oven, means for transferrlng said trays from.

from said oven to said heater, a pluralityof endless conveyors movable vertically through said oven, means carried' by the con Veyors to support trays bearing the substances to be baked, a cooling tower, an linlet from said oven to the cooling tower, a pluralityk of endless conveyors movable vertically in said tower, means carried by said conveyors to support said trays, means for automatically transferring trays from the oven tothe cooling tower and vmeans for preventing egress of hot air from said oven to said tower at the transfer point.

6. A baking apparatus comprising an insulated oven, an air heater, a plurality of independently controllable inlets in said oven connected with said heater, exhaustoutlets from said-oven to said heater, a plutically in said tower, means carried by said rality of endless conveyors movable vertically through said oven, means carried by the conveyors to support trays bearing the substances to be baked, a cooling tower, an inlet from sai-d 'oven to the cooling tower, a plurality of endlessv conveyors movable verconveyors to support' said trays, endless con- 'veyors extending laterally across said oven,

i means carried by said conveyors for removing trays from the oven 'conveyors to the coollng tower conveyors and means forpreventing egress of hot air through the inlet..

from the oven to the cooling tower.

7. A baking apparatus `comprising an insulated oven, an air heater, a-plurality of independently` controllable inlets in said oven connected with said heater, exhaust outlets from said oven'to said heater, a plurality of endless conveyors movable vertically through said oven, means carried by the conveyors to support trays bearing the substances to be baked, a coolin tower, an iuletvfrom lsaid oven to the coo` ing tower, a plurality of endless conveyors movable vertically in said tower, means carried by said t, trolling sai conveyors to support said trays, endless conveyors extending laterally across said oven,

means carried by said conveyors for removf ;tl1e cooling tower.

8. A baking apparatus comprising an insulated oven, an air heater, a plurality of independently controllable inlets in said oven connected with said heater, exhaust outlets from said oven to said heater, a plurality of endless conveyors movable vertically through said oven, means carried by the conveyors to support tra s bearing the substance to be baked, a coo ing tower," an inlet from said oven to the cooling tower, a plurality of endless conveyors movable vertically -in said tower at a speed slower than those in the oven, means carried by said cooling tower conveyors to sup ort said trays such means being more close y spaced than those carried by the oven conveyors, means for automatically transferring trays from the oven to the cooling tower and means for preventing egress of hot air Ifrom said oven to said tower at the transfer point.

9. A baking apparatus comprising an oven, an, air heater, means for maintainin a continuous circulation of air through sai r oven and heater, a cooling chamber, means for maintaining a continuous passage of coldv air through said chamber, a power shaft, conveying devices in said oven and cooling chamber and between them and drivingconnection between said power shaft and conveying devices whereby the cooling chamber conveying devices are driven at a proportionately slower speed than the oven conveying devlces.

10. A baking apparatus comprisin van oven, an air heater, air inlet trunks an air exhaust trunks in said oven, communications between all of said trunks and the air heater, a plurality of openin s in said .inlet trunks, independently opera le bailies controllin said openings, conveying means maintaining continuousA movement within said oven of the substances being baked independently controllable means for deliecting hot aironto said substances, and a cooling chamber operating in conjunction with said oven. y

11. -A baking apparatus comprisin an oven, an air heater, air inlet trunks an air exhaust trunks in said oven, communications between all of said trunks andthe air heater, a plurality of openin s in said inlet trunks, -inde endently opera le` bales consaid oven of the substances being baked,ra plurality. of deilectors disposed adjacent s openings, conveying meansf maintaimng continuous movement within a yso each hot-air inlet, independently operable means controlling each set of deflectors, a cooling chamber, conveying means 'main-` taining continuous movement therethrough of substances baked in said oven, and means for causing a continuous movement of cooling air through said chamber.

12. A baklng apparatus comprising an oven, an air. heater, air inlet trunks and air exhaust trunks in said oven, communications between all of said trunks and the lairl heater,a plurality of openings in said inlet trunks, independently operable bales controlling said openings, a plurality of endless conveyors movable verticallyy in said oven, means carriedl by the conveyors to support trays bearing the substancesto be baked, a cooling tower, an inlet from the oven to the cooling tower, a plurality of endless conveyors movable vertically in said tower, means carried by said conveyors to. support said trays, means for automatically transferring trays fr'om oven to cooling tower and means for preventing egress of hot air from said oven to said tower at the transfer oint.

13.v A aking apparatus comprising an oven, an air heater, air inlet trunks and air exhaust trunks in said oven, communications between all of said trunks and the air heater, a lurality of openings in said inlet trunks, independently operable baffles controllingv .said openings, a plurality of endless conveyors movable vertically in said oven, means carried by the conveyors to support trays bearing the substances to be baked, a cooling toweran inlet from the oven to the cooling tower, a plurality of endless conveyors movable vertically in said tower, means carried by said conveyors to support said trays, endless conveyors extending laterally across said oven, means carried by said conveyors for removing trays from the oven conveyors to the cooling tower conveyors and means for preventing egress of hot air through the inlet from the oven to the cooling tower.

14. A baking apparatus comprising an oven, an air heater, air inlet trunks and air exhaust trunks in said oven, communications between all of said trunks and the air heater, a plurality of openin s in said inlet trunks, independently opera le baiies controlling said openin s, a plurality of endless conveyors movab e vertically in said oven, means carried by the conveyors to support trays bearing the substances to. be baked, a cooling tower, an inlet from the oven to the cooling tower, a plurality of endless conveyors movable vertically in said tower, means carried by said conveyors to supportsaid trays, endless conveyors extending laterally across said oven, means carried by said conveyors for removing trays from the oven conveyors to the cooling tower conveyors, an inlet for cold air at the I base of said cooling tower and an outlet for heated air in said cooling tower at a point below the inlet from the oven to the cooling tower.

y15.'A baking apparatus comprising an oven, an air heater, air inlet trunks and air exhaust trunks in said oven, communications between all-of said trunks and the 'air heater, a plurality of openin s in said inlet trunks, 'independently opera le bailies controlling said openings, a plurality of endless conveyors movable vertically in said oven, means carried by the conveyors to support trays bearing thelsubstances to be baked, a cooling tower, an inlet from the oven to the cooling tower, a plurality of endless conveyors movable vertically in said tower at a speed slower than those in the oven, means carried by said cooling tower conveyors to support saidtrays such means being more closely spaced than those carried by the oven conveyors, means for automatically transferring trays f'rom the oven to the cooling tower and means for preventing egress of hot air from said oven to said tower at the transfer point.

16. A baking apparatus comprising an insulated oven, an air heater means for maintaining continuous air circulation between said oven and heater, means whereby heated air enters said oven through a plurality of controllable inlets, an inlet in the base of said oven, an endless conveyor adapted to deliver trays of substancesto be baked through said inlet endless conveying devices movable vertically in said oven, a cooling tower, an endless conveyor for transferring baked substances from said oven to said tower, endless conveying devices movable vertically in said cooling tower, an outlet in the base of said tower, an endless conveyor operating to discharge trays through said outlet, a power shaft and driving connections from said power shaft to all of said conveyor devices.

17. A baking apparatus comprising an insulated oven, means for introducing hot air at a plurality 0f independently controlT lable inlets in said oven, a cooling chamber,

means for causing currents of cooling air a to pass through .said chamber means for causing contmuous movement of substances under treatment through said oven and cooling chamber, independently operable groups of deflecting devices controlling the clrculation. of hot air around the substances bein baked and exhaust outlets connecting sai oven with the source of hot air supply.

18.` A baking apparatus comprislng an insulated oven, an air heater,A air inlet trunks and air exhaust trunks in said oven, communications between all of said trunks and the air heater, a plurality of openin' s in said inlet trunks, independently operab e said oven, supports carried by, caio cc ors to receive trays' of substances to baked, independently controllable means for deilecting het air onto the substances to be baked, a cooling tower, `means for trans ferring baked substances automatically from said oven to said tower, and means for pr'eventing escape of hot air from said oven to said tower. l

19. Abaking apparatus comprising an insulated oven, an air heater, air inlet trunksand air exhaust trunks in said oven, communications between all oi said trunks and the air heater, a lurality of openings in said inlet trunks, in ependently operable bellies controlling said openings, a plurality ot endless conveyors movable vertically in said oven, supports carried by said conve ors to receive trays of substances to be bake independently controllable means for deflecting hot air onto the substances to be baked, a cooling tower, an endless conveyor adapted 25 to transfer said trays from the top oit said Joven to the top of said cooling tower, a plu rality of endless conveyors movable vel-ti cally 1n said cooling tower, supports carried by Said conveyors-to receive said trays, an

inlet for cooling air at the base of said tower, an outlet for heated air near the top of said tower but below the entry from the oven, a power shaft, driving connections between said power shaft and all of said conveying devices whereby the cooling tower conveyors are driven at a speed proportionately slower than that of the oven conveyors and an outlet formoisture at the top of lsaid oven.

20. A baking apparatus comprising an oven, a casing connected to said oven, a plurality of heated conduits disposed within said casing, means causing the passage of air to be heated around said conduits, means for causing a continuous circulation or" air through said oven and casing, means for causing substances under treatment to ascend through said oven and a cooling tower operating in conjunction with said oven.

21. A baking apparatus comprising an oven, a casing connected to said oven, a plurality of heated conduits disposed within said casing, a plurality of heat distributing devices projecting from the to of each conduit, means causing air to be cated to pass across the tops of said conduits, means for causing a continuous circulation 'of air through said oven and casing, a cooling tower adjacent said oven and means causing substances under treatment to ascend through said oven and to descend through said coolin tower.

22. A ba ring apparatus comprising an oven, a casing adgacent said oven, a plurality of hosted conduits having curved upper surfaces disposed within said casing, a

a plurality of air outlets in said oven, conncctions between said inlets and outlets and said casing and a i'an interposed in said connections.

23. fr. baking apparatus comprising an foven, a casing adjacent said oven, a plurality o heated conduits having curved upper surfaces disposed within said casing, a plurality of cylindrical heat distributing devices projecting from the top of each conduit, battles within said casing to compel f to pass across the tops of said conduits, plurality of independent controllable air inlets in said oven, a plurality of exhaust outlets in said oven, connections between said inlets and outlets and said casing, a fan terposed in said connections, a cooling tower adjacent said oven and means for conveying substances under treatment through said oven and tower.

24. A baking apparatus comprising an in sulated oven, an insulated casing adjacent said oven, a plurality of heated conduits disposed within said casing, means whereby air 1s caused to circulate around said conduits, a plurality of independently controllable inn lets in said oven, a plurality ci' exhaust outlets in said oven, connections between said inlets and, outlets'and said casing, a plurality of endless conveyors movable vertically through said oven, means carried by the corr veyors to support trays bearing the substances to be baked,'a cooling tower, an inlet from said ovento the cooling tower, a plurality of endless conveyors movable vertically in said tower at la speed slower than those in the oven, means carried bysaid cooling tower conveyors to support said trays, means ior automatically transferring trays from the oven to the cooling tower and means for preventing egress ci hot air from said oven to said tower at the transfer point,

25. A baking apparatus comprising an oven, air inlet trunks and air exhaust trunks in said oven, a Aplurality of openings in said inlet trunks, independently operable bales.

controlling said openings, conveying means maintaining continuous movement within said oven of the substances bein baked, a plurality of deflectors disposed adJaoent each hot air inlet, independently operable means controlling each set of delectors, a casin adjacent said oven, a plurality of heated conduits disposed within said casing, means whereby air isy caused to circulate around said conduits, connections between said air inlet andvv exhaust trunks and said casing, means for maintaining a4 continuous circulation of air through said oven and casing, a cooling chamber, conveying means maintaining continuous movement tlierethrcnce ci lil@ substances baked in said oven and means for causlng a contlnuous movement of coollng air through said chamber. E

26. A baking apparatus comprising an oven, a casing adjacent thereto, a plurality of heated conduits disposed Within said casing, a plurality of heat distributing devices projectmg from the top of each conduit, means compelling air to pass across the tops 10 of said conduits, a plurality of inlets for the substances under treatment and a cooling 15 chamber operating in conjunction with said oven.

In Witness whereof I afiix my signature.

ROWLAND GREENWOOD. 

